let arr = ['name', 55, true];
const it = arr.entries();
console.log(it);//Array Iterator
console.log(it.next());
/**结果
{
  "value": [ 0, "name"],
  "done": false
}
*/
console.log(it.next());
/**结果
{
  "value": [ 1, 55 ],
  "done": false
}
*/
